He tweeted a comment which directly referenced Navarro's.
Surrounded by G7 leaders, President Donald Trump, and Trump alone, can be seen sitting - arms crossed. German Chancellor Angela Merkel, who also attended the summit, told German public television that she found Trump's tweet disavowing the G-7 statement "sobering" and "a little depressing".
Trump's comments after a historic summit in Singapore with North Korean leader Kim Jong Un were the president's most extensive on the matter since he tweeted that Trudeau was "very dishonest and weak" and raised the prospect of tariffs against auto imports, a move that would imperil the Canadian economy. Conspiracy theories, jokes and memes started bubbling up after the Canadian Prime Minister's eyebrows appeared uneven during his press conference with French president Emanuel Macron.
The former Conservative prime minister said that while he believes the dispute is serious, that doesn't make it "lethal". John McCain and ex-FBI director James Comey - who Trump unceremoniously fired past year - took to Twitter to offer their support. Can't do it in person. "We joined the communique in good faith", Kudlow said.
Trump adviser Peter Navarro, meanwhile, said Tuesday he made a mistake when he said "there's a special place in hell" for Trudeau.
Asked if these were statements from the President, Navarro said they were his words, but that they reflected "the sentiment that was on Air Force One".
"I want to pay a particular tribute to Prime Minister Trudeau for his leadership and skilful chairing, which enabled us after two days of negotiation between leaders to agree actions and a shared approach on some of the most pressing challenges facing the worldwide community and our citizens", she told parliament.
Speaking to the House of Commons, May said the other G-7 nations "expressed deep disappointment at the unjustified decision of the United States to apply tariffs to steel and aluminum imports" and urged dialogue to avoid "tit-for-tat escalation".
"That's what weak, dishonest Justin Trudeau did", Navarro said.
Earlier, the White House escalated the unprecedented criticism against Trudeau, branding him a back-stabber unworthy of Trump's time.
"It was a betrayal", Kudlow said on CNN's "State of the Union".
For his comments, Trump fired back on Twitter, stating, "Please tell Prime Minister Trudeau and President Macron that they are charging the US massive tariffs and create non-monetary barriers".
"In general, it was an attack on the president", he claimed.
Trump's carrot-and-stick rhetoric on North Korea matched his message for the G-7 on trade. "We need to stand with our democratic allies". "You want a tariff-free [arrangement]. But actually we were just talking, the whole group, about something unrelated to everything, very friendly". He described all seven leaders coming together to sign the joint declaration despite having "some strong, firm conversations on trade, and specifically on American tariffs".
Mr Trump tweeted: "PM Justin Trudeau of Canada acted so meek and mild during our G7 meetings only to give a news conference after I left saying that, "US Tariffs were kind of insulting" and he 'will not be pushed around'".